I use vacuum seal for the chickens, but I use butcher paper for the geese. I do a double wrap.
I just pull off a long sheet of paper and roll them up and fasten the edges like a Christmas present. Then I wrap them again in another sheet of paper and completely seal every edge with freezer tape.
Wherever there are two edges of paper come together, I fold them a couple of times to make a good airtight seal.
Air won't get through the paper, so all you have to do is not have any leaks in the packaging where air could get in.
Oh... after the first layer of paper is on, I push the legs as close together as I can get them and then wrap a couple of turns of tape to keep them close together. They take up less freezer space that way.
Thank you for the tips. This is my first time to raise chickens for meat and I went with a heritage breed and only have 8 birds to process. Otherwise I would have either invested in vacuum sealer or the heat shrink bags.